Measurement of power line harmonics-microprocessor based

摘要

Measurement of harmonic levels is an important preliminary task in the analysis of the ill-effects of the harmonic pollution. This paper aims at developing a microprocessor based system for the measurement of harmonic amplitudes and phase angles. The voltage/current signals are sampled at the lowest rate possible to resolve up to the 32nd harmonic. Based on the finite set of discrete samples, the Discrete Fourier Transform coefficients are computed using the Fast Fourier Transform approach. The basic results of FFT calculations are in the form of 32 discrete complex values giving harmonic magnitude and phase at each of these frequencies. The above procedure is implemented on the 8085 processor, using 8253 for getting equispaced intervals. Further the harmonic waveform could be viewed on the oscilloscope, by the inverse FFT computation arranged on the 8085 processor.